Animal Behavior Core

The Acoustic (ASR) and Tactile Startle Response (TSR) are well-established tests for evaluating the complex brainstem-mediated reflex pathway. We use the San Diego Instruments SR Apparatus for these tests.

We also test for pre-pulse inhibition (PPI), a well-established measure for testing sensorimotor gating. PPI is abnormal in several human disorders, such as schizophrenia and major depression. ASR and PPI test methods and responses are nearly identical in humans and rodents, offering homologous comparisons across species.

The Forced Swim Test (FST) is a well-known test for assessing stress responses including HPA axis markers such as ACTH, corticosterone and others. It also serves as a test of depression (the Persolt test of swimming despair). The Persolt test evaluates swimming immobility after a training session in which the animal is placed in a cylinder half-filled with water. We can score the FST using video tracking software.

We record test animal stride using an inclined runway covered with white paper and ink painted on the plantar surface of the animal’s feet. We score tracks of the animal and measure stride length and width, foot placement, splay and symmetry. This test measures motor control and provides information about cerebellar function.

These tests measure function of the test animal’s cerebellum and balance (otolith for static and semicircular canals for dynamic balance). A square or round beam is suspended from one end on an upright pole and attached at the other end to an enclosed escape box.  The animal learns to cross the beam to the escape box, which is dark inside. Once it masters the task, it is placed on progressively narrower or smaller diameter beams. We track the animal’s crossing time and the number of foot slips.

These tests use elevated plus (EPM) or elevated zero (EZP) mazes to test anxiety-like behavior. The mazes are similar, with two open and two  closed  arms or quadrants (closed sections have high, black acrylic walls). Animals are tested for five minutes, and the time spent in the open areas provides the principal index of anxiety. These tests are video tracked and computer scored using AnyMaze software from Stoelting Instruments.

This test places a grid of foreign objects (marbles) in a standard cage filled with bedding (measured to a standard depth). Animals are tested for 30 minutes, and the number of objects buried is recorded. This is a test of defensive anxiety.

The test measures immobility in the animal by suspending it by the tail using an acrylic plate with a hole for the tail to pass through. Once the animal determines that escape is impossible, it stops struggling. This test can show the effect of antidepressants and sedatives on the animal, and is often used to provide converging evidence for results from Forced Swim Testing (FST). Animals are suspended for single trials of no more than six minutes, and the time spent immobile is manually recorded.  This test is available only for use with mice.

This fully automated test is conducted for various time intervals, but typically lasts 60 minutes. The system records horizontal activity, total distance traveled (cm), central versus peripheral movement or time, vertical movement, repetitive movements and time the test animal spends exploring different zones of the environment. The test measures exploration in response to a novel environment, habituation rate (as the environment become familiar) and baseline spontaneous ambulation. The locomotor activity test can provide data on the test animal’s basal ganglia (caudate-putamen) function.

This test evaluates the time it takes the test animal to move from light to dark areas in a divided test chamber, and dwell time between the two chambers. The test uses our photocell-equipped locomotor activity test chambers.

This is the most widely used test for measuring spatial navigation and reference memory. The test animal is placed in an open, circular pool in which there is a submerged platform. A series of tests can measure a variety of memory and navigation tasks, as the test animal swims to the platform from various locations, or tries to find the platform after it has been removed. Tests are video-tracked using AnyMaze, and analysis can provide information on the test animal’s hippocampus-dependent reference memory and prefrontal cortex working memory.

This uses a labyrinthine maze with nine T-shaped cul-de-sacs branching from a central (but circuitous) channel leading from the start to the goal. The test is conducted in complete darkness (monitored with an infrared light emitter and camera) to eliminate distal cues, thus testing the animal’s “sense of direction” or ability to navigate using route-based egocentric cues (i.e., internal cues).

We record latency time to find the escape and errors of commission (entry into blind alleys).  The test provides a method for evaluating an animal’s entorhinal cortex, where grid cells integrate information from the hippocampus and the pre- and post-subiculum (where head direction cells are located). 

This test uses the animal’s reaction to a novel object as an avenue to evaluate dorsal hippocampal function. The animal is familiarized with two identical objects, and then is placed in a test space with one of the familiar objects paired with a novel object. We measure time spent exploring the novel object, which reflects intact memory for the original object.

This test uses cued conditioning to evaluate amygdala function and contextual conditioning to evaluate function of the hippocampus, subiculum, cingulate, prefrontal and perirhinal cortices. After being conditioned by pairing a neutral stimulus (a tone) to an aversive stimulus in a specific test environment it will associate the tone with the aversive stimulus.  The animal is placed in the test chamber a second time and observed for reactions to the chamber alone or an altered test chamber accompanied by the tones.

Using the equipment and conditioning designed for the Conditioned Fear test, we are able to evaluate the effect of pre-exposure to a stimulus on conditioning. Animal models of schizophrenia and autism show an impairment of latent inhibition, which mirrors human characteristics of those diseases.

This test can be modified to fit a PI’s specific needs. Typically, the test involves familiarizing the test animal with a test chamber, and then observing changes to the animal’s behavior after it is injected with one of a variety of drug challenges. We typically test animals using indirect dopaminergic agonists, specific dopamine D1 and D2 agonists and antagonists, cholinergic-muscarinic antagonists and glutamatergic-NMDA receptor antagonists. We also have experience using a variety of other agents for this test.

This test places the animal in a three-compartment test chamber.  The two end compartments each contain a small cage with wide slits to allow an animal on either side of the cage to contact and smell a conspecific on the other side.  For the test, a “stranger” mouse or rat is placed in the cage inside one of the end compartments.  The test subject is placed in the middle compartment and allowed to explore freely.  The time the test subject spends with the cage with the conspecific in it versus time in the opposite end compartment with the empty cage reflects social preference for another animal of the same species and strain.  There is evidence that social preference in rodents has some relationship to human sociability.